Variable pitch propeller for small boats



D. 1.. MILLER ETAL VARIABLE. PITCH PROPELLERFOR SMALL BOATS Sept. 15, 1964 2 Sheets-Shet 1 DONALD L. MILLER LAWRENCE W VIN THER INVENTORS Filed May 12, 1964.

ATTORNEY Sept. 15, 1964 D. L. MILLER ET AL 3,148,735

VARIABLE PITCH PROPELLER FOR SMALL BOATS Filed May 12, 1964 2 Sheets-Sheet 2 FIG. 4-.

DONALD L. MILLER LA WRENCE W VIN THER mvmvrons AT TORNE Y United States Patent Lawrence W. Vinther, 10420 Gooding Drive, Dallas,

Tex.

Filed May 12, 1964, Ser. No. 366,869

7 Claims. (Cl. 170-16952) v This invention relates to a variable pitch propeller for small boats, and it concerns more particularly hydraulically operable means, adapted to be controlled manually from inside a boat, for application to the lower drive portion of an outboard engine, or alternatively, to out board drive means for an inboard engine having like structure, for varying the pitch of the propeller blades while the boat is in operation.

The invention is particularly useful in Water skiing, in which from one to four persons on skis are towed behind a boat, and in which the pitch of the propeller blades advantageously may be adjusted while the boat is in operation to provide the power needed to get the boat in motion against the resistance of the skis and to get the skis out of the water and in planing position, and thereafter to provide the speed which is needed to keep the skis afloat after the boat is in motion.

When the pitch of the propeller blades is fixed the pitch thereof necessarily must be adjusted for maximum power at a sacrifice of speed, and the speed of the boat may be increased only by increasing the speed of the engine, which may be uneconomical. If the pitch of the propeller blades is adjusted for maximum speed at a sacrifice of power cavitation may result, as the blades are turned at high speed through the water, while the boat is in its at rest position, and no forward thrust may be effected, so that the boat does not move.

When using the boat for fishing, the pitch of the propeller blades advantageously may be adjusted while the boat is in operation to provide the power which is needed initially to get the boat in motion in planing position, and thereafter to provide the high ratio of boat speed to the speed of the engine which is needed to get to the fishing site, and finally, to provide the high ratio of engine speed to the speed of the boat which is needed for trolling.

In speed boats for use in racing, the pitch of the propel ler blades likewise advantageously may be adjusted while the boat is in operation to provide the power which is needed initially to get the boat in motion and in planing position, and thereafter to provide the high ratio of boat speed to the speed of the engine which is needed after the boat is in motion.

The invention will be readily understood by referring to the following description and the accompanying drawing, in which:

FIG. 1 is a fragmentary elevational view, partly in section taken on a median line, showing a rearward section of the lower drive portion of an outboard engine having the invention incorporated therein and showing the propeller blades in one of their adjusted positions;

FIG. 2 is a sectional elevational view taken on the line 22 of FIG. 1; v

FIG. 3 is a fragmentary top plan view showing the extreme rearward part of the apparatus illustrated in FIG. 1 and showing one of the propeller blades in another of its adjusted positions;

FIG. 4 which is a continuation of the view illustrated in FIG. 1, is a fragmentary elevational view on an enlarged scale, partly in section taken on a median line, showing a forward section of the lower drive portion of said outboard engine having the invention incorporated therein;

FIG. 5, which is a continuation of the view illustrated in FIG. 4, is a fragmentary elevational View on an enlarged scale, partly in section taken on a median line, showing a portion of the apparatus of the invention which in use is positioned inside the boat; and

FIG. 6 is a longitudinal view, partly in section taken on a median line, showing the propeller shaft and portions of the apparatus associated therewith as illustrated in FIGS. 1 and 4.

f Referring to the drawing, the numeral .1 designates generally the lower drive portion of an outboard engine, which includes a housing, indicated generally by the numeral 2, and a horizontally extending propeller shaft 3 which is rotatable about its axis and is driven in the usual manner. V

Thepropeller shaft 3 is journaled in bearings 4, 5 positioned forwardly and rearwardly of the housing 2, respectively, and extends rearwardly beyondthe housing 2 for engagement by a propeller assembly as hereinafter de scribed.

In accordance with the invention the propeller shaft 3, which is in other respects similar to propeller shafts which are commonly employed for the purpose described, has a central longitudinal bore 6 which is coextensive with its length. The bore 6 is enlarged beginning at its forward end, as at 7.

An elongated rod 8, which is slightly longer than the propeller shaft 3 and advantageously may be made of brass or bronze whereby its is slidable relative thereto, is received in the bore 6 and is movable reciprocally therein a comparatively short distance, which may be of the order of about inch, for example.

The. rod 8 has a threaded end portion 9 which extends rearwardly beyond the adjacent end of the propeller shaft 3, and has an enlarged opposite end portion 10 which is received in the enlarged forward end portion 7 of the bore 6. v j I A compression spring 11, which surrounds the rod 8 immediately adjacent its enlarged end portion 10 and is received in the enlarged forward end portion 7 of the bore 6, acts on the enlarged end portion 10 of the rod 8 and a forwardly facing internal shoulder formed by the enlarged forward end portion 7 of the bore 6 to bias the rod 8 forwardlyrelative to the propeller shaft 3.

A propeller, indicated generally by the numeral 12, has a central hub 1-31which is connected to the propeller shaft 3 rearwardly of the housing 2 and is rotatable therewith, and a plurality of blades 14 which are connected to the hub 13 and are rotatable therewith, the blades 14' being adjustable rotatively about a radial axis to vary their pitch as hereinafter described. I

The hub 13 is generally cylindrical and includes forwardly and rearwardly extending inner tubular portions 15, 16 immediately surrounding the propeller'shaft 3 ad-' jacent its rearward end, an integral circular portion 17 betweenthe'inner tubular portions 15, 16 extending radially outwardly therefrom, and an integral outer cylindrical portion 18 adjacent the outer periphery of the circular.

portion 17 extending forwardly therefrom, in concentric,

coaxial, spaced apart relation to the forwardly extending inner tubular portion 15. The rearwardly extending in ner tubular portion 16, is connected to the propeller shaft 3 by shear pins 19 whereby the hub 13 is rotatable with the propeller shaft 3.

Each ofthe blades 14 has an integral stub shaft 20' thereon whichis passed through a corresponding opening therefor inthe outer cylindrical portion 18 of the hub 13 and is journaled in a cylindrical Teflon bearing 21 therefor received in said opening whereby the blade 14 is adjustable rotatively about a radial axis.

A snap ring 22, which is received in a corresponding groove therefor in the stub shaft 20, in abutting engagement with the adjacent end of the bearing 21, secures the blade 14 against displacement from the hub 13.

A blade adjusting member 23, which is generally conical and which has a central bore 24 corresponding to the bore 6 of the propeller shaft 3, is received on the rod 8 adjacent the threaded end portion 9 thereof with its smaller end facing rearwardly. The bore 24 of the blade adjusting member 23 is enlarged beginning at its forward end, as at 25, for engagement by the rearwardly extending inner tubular portion 16 of the hub 13.

The blade adjusting member 23 is secured between a rearwardly facing shoulder on the rod 8 near the rearward end of the propeller shaft 3 and a nut 26 which is applied to the threaded end portion 9 of the rod 8. An annular Teflon bearing 27 is received on the rod 8 between the nut 26 and the adjacent end of the blade adjusting member 23 so that the rod 8 is rotatable, as by frictional engagement with the propeller shaft 3, independently of the blade adjusting member 23.

' The blade adjusting member 23 has openings 28 extending radially outwardly from the enlarged forward end 25 of the bore 24 whereby the shear pins 19 are conveniently accessible.

The blade adjusting member23 has a peripheral groove 29 near its forward end, and each of the blades 14 has an angularly bent projection 30 on a trailing edge portion thereof, relative to the direction of movement of the boat, positioned eccentrically of the stub shaft 20 and extending substantially parallel thereto, in sliding engagement with the groove 29 whereby the blades 14 are adjustable rotatively about a radial axis in response to longitudinal movement of the rod 8 in either direction relative to the propeller shaft 3.

A forward extension of the housing2, indicated by the numeral 31, is connected thereto by bolts 32. A hydraulic cylinder 33, which is formed in the forward extension 31 and is aligned axially with the propeller shaft 3, has a piston 34 movable reciprocally therein.

A piston rod 35, which is connected to the piston 34, is received in a cup shaped Teflon bearing 36 which in turn is received in a recess therefor in the enlarged forward end portion of the rod 8 whereby the rod 8 is movable. longitudinally in a rearward direction in response to fluid pressure applied to the opposite side of the piston 34, against the resistance of the spring 11, while at the same time the rod 8 is rotatable about its axis, as by frictional engagement with the propeller shaft 3, independently of the piston rod 35. i

The housing 2 is filled with oil, and a gasket 37 is provided between the forward extension 31 and a corresponding opening formed in the housing 2. A pair of sealing rings 38 are provided on the opposite side of the housing 2, rearwardly of the rear bearing 5.

i A resilient O-ring 39, which is received in a peripheral groove therefor in the rod' 8, between the rod 8 and the bore 6, is positioned near the rearward end of the propeller shaft 3 whereby Water is excluded from the interior of the bore 6.

A power cylinder 40, which advantageously may be mounted on a bracket 41 positioned inside a boat, has one of its ends connected by a fluid conduit 42 and fluid passages 43 in the housing 2 and the forward extension 31, respectively, to the end of the hydraulic cylinder 33 opposite the propeller shaft 3.

A reservoir 44 abo 'e the power cylinder 40, which has a filler opening for hydraulic fluid normally closed by a cap 45, is connected by a fluid passage 46 to the power cylinder 40 whereby hydraulic fluid is supplied to the power cylinder 40 as needed.

A piston 48 is movable reciprocally in the power cylinder 40, and a piston rod 42, which is connected at one end to the side of the piston 48 opposite the fluid conduit 42, has a cam follower 50 on its opposite end. A hand lever 51. which is fulcrumed on a bracket 52 depending form the bracket 41, as at 53, at a point which is aligned 54 thereon for engagement by the cam follower whereby the piston 48 is movable reciprocally in the power cylinder 40 in response to manual operation of the lever 51.

The degree of leverage is such that a substantially greater movement of the lever 51 is required to effect limited movement of the rod 8 in either direction, to thereby adjust the pitch of the blades 14, in response to reciprocal movement of the piston 48.

The lever 51 is yieldably secured against pivotal displacement from any position in which it may be set by frictional engagement of the cam follower 50 with the cam surface 54 in response to the action of the spring 11.

The invention may be modified in various ways without departing from the spirit and scope thereof.

We claim:

1. In outboard drive means for an engine driven boat, the combination of a housing, a horizontally disposed propeller shaft having bearings in said housing whereby it is supported for rotation about its axis, said propeller shaft extending rearwardly beyond said housing and having a longitudinal bore coextensive therewith, said bore being enlarged beginning at its forward end, an elongated rod movable reciprocally in said bore, said rod extending rearwardly beyond the adjacent end of said propeller shaft and having an enlarged forward end portion received in the enlarged forward end portion of said bore, a compression spring surrounding said rod received in the enlarged forward end portionof said bore acting on said rod to bias it forwardly, a propeller assembly on said propeller shaft, rearwardly of said housing, including a central hub connected to said propeller shaft and a plurality of propeller blades extending radially outwardly from said central hub, each of said blades having means whereby it is pivotally connected to said central hub for rotative adjustment about a radial axis, and having an integral projecting element positioned eccentrically of said axis and spaced laterally therefrom operable to turn the blade about said axis, a blade adjusting member having means whereby it is loosely connected to said rod for reciprocal movement therewith and extending radially out wardly therefrom, rearwardly of said central hub, said blade adjusting member having means for abutting engagement with the integral projecting elements of said blades whereby said blades are each adjustable rotatively about a radial axis in response to reciprocal movement of said rod, a forward extension of said housing having a hydraulic cylinder therein aligned with said propeller shaft, a piston in said hydraulic cylinder having a piston rod in abutting engagement with the enlarged forward end portion of said rod and rotatable relative thereto, a power cylinder having a supporting bracket and having fluid conduit means whereby one of its ends is in fluid communication with the end of said hydraulic cylinder opposite said propeller shaft, a piston in said power cylinder having a piston rod extending outwardly from the end thereof opposite said one ofits ends, a hand lever pivotally connected to said bracket and fulcrumed near one of its ends at a point which is aligned axially with said last mentioned piston rod, a cam surface on said lever adjacent its connected end, and a cam follower on said last mentioned piston rod, the arrangement being such that said blades are adjustable rotatively about a radial axis, to thereby vary their pitch, in response to pivotal movement of said lever.

2. The structure of claim 1, said outboard drive means comprising the lower drive portion of an outboard engine.

3. The structure of claim 1, said means whereby each of said blades is pivotally connected to said central hub for rotative adjustment about a radial axis comprising an integral stub shaft on the blade journaled in a bearing therefor in said central hub, said integral projecting element being angularly bent and extending substantially parallel to said stub shaft, and said blade adjusting member being generally conical and having a peripheral groove therein for engagement by the integral projecting elements of said blades.

4. The structure of claim 1, and a reservoir for hydraulic fluid in fluid communication with said power cylinder whereby said power cylinder is maintained full of hydraulic fluid at all times.

5. The structure of claim 1, the arrangement being such that said lever is adapted to be secured in any of its adjusted positions by frictional engagement of said cam follower with said cam surface in response to the action of said compression spring.

6. The structure of claim 1, the degree of leverage being such that substantially greater pivotal movement of said lever is required to effect limited longitudinal adjustment of said rod relative to said propeller shaft.

7. In outboard drive means for an engine driven boat, the combination of a housing, a horizontally disposed propeller shaft having bearings in said housing whereby it is supported for rotation about its axis, said propeller shaft extending rearwardly beyond said housing and having a longitudinal bore coextensive therewith, said bore being enlarged beginning at its forward end, an elongated rod movable reciprocally in said bore, said rod extending rearwardly beyond the adjacent end of said propeller shaft and having an enlarged forward end portion received in the enlarged forward end portion of said bore, a compression spring surrounding said rod received in the enlarged forward end portion of said bore acting on said rod to bias it forwardly, a propeller assembly on said propeller shaft, rearwardly of said housing, including a central hub connected to said propeller shaft and a plurality of propeller blades extending radially outwardly from said central hub, each of said blades having means whereby it is pivotally connected to said central hub for rotative adjustment about a radial axis, and having an integral projecting element positioned eccentrically of said axis and spaced laterally therefrom operable to turn the blade about said axis, a blade adjusting member having means whereby it is loosely connected to said rod for reciprocal movement therewith and extending radially outwardly therefrom, rearwardly of said central hub, said blade adjusting member having means for abutting engagement with the integral projecting elements of said blades whereby said blades are each adjustable rotatively about a radial axis in response to reciprocal movement of said rod, and means for adjusting longitudinally within predetermined limits the position of said rod relative to said propeller shaft.

References Cited in the file of this patent UNITED STATES PATENTS 1,644,378 Hirschler Oct. 4, 1927 1,802,808 DeNorde Apr. 28, 1931 2,383,440 Baxter Aug. 28, 1945 3,054,458 Marsico Sept. 18, 1962 3,092,186 MacLean June 4, 1963 FOREIGN PATENTS 17,652 Great Britain 1902 

1. IN OUTBOARD DRIVE MEANS FOR AN ENGINE DRIVEN BOAT, THE COMBINATION OF A HOUSING, A HORIZONTALLY DISPOSED PROPELLER SHAFT HAVING BEARINGS IN SAID HOUSING WHEREBY IT IS SUPPORTED FOR ROTATION ABOUT ITS AXIS, SAID PROPELLER SHAFT EXTENDING REARWARDLY BEYOND SAID HOUSING AND HAVING A LONGITUDINAL BORE COEXTENSIVE THEREWITH, SAID BORE BEING ENLARGED BEGINNING AT ITS FORWARD END, AN ELONGATED ROD MOVABLE RECIPROCALLY IN SAID BORE, SAID ROD EXTENDING REARWARDLY BEYOND THE ADJACENT END OF SAID PROPELLER SHAFT AND HAVING AN ENLARGED FORWARD END PORTION RECEIVED IN THE ENLARGED FORWARD END PORTION OF SAID BORE, A COMPRESSION SPRING SURROUNDING SAID ROD RECEIVED IN THE ENLARGED FORWARD END PORTION OF SAID BORE ACTING ON SAID ROD TO BIAS IT FORWARDLY, A PROPELLER ASSEMBLY ON SAID PROPELLER SHAFT, REARWARDLY OF SAID HOUSING, INCLUDING A CENTRAL HUB CONNECTED TO SAID PROPELLER SHAFT AND A PLURALITY OF PROPELLER BLADES EXTENDING RADIALLY OUTWARDLY FROM SAID CENTRAL HUB, EACH OF SAID BLADES HAVING MEANS WHEREBY IT IS PIVOTALLY CONNECTED TO SAID CENTRAL HUB FOR ROTATIVE ADJUSTMENT ABOUT A RADIAL AXIS, AND HAVING AN INTEGRAL PROJECTING ELEMENT POSITIONED ECCENTRICALLY OF SAID AXIS AND SPACED LATERALLY THEREFROM OPERABLE TO TURN THE BLADE ABOUT SAID AXIS, A BLADE ADJUSTING MEMBER HAVING MEANS WHEREBY IT IS LOOSELY CONNECTED TO SAID ROD FOR RECIPROCAL MOVEMENT THEREWITH AND EXTENDING RADIALLY OUTWARDLY THEREFROM, REARWARDLY OF SAID CENTRAL HUB, SAID BLADE ADJUSTING MEMBER HAVING MEANS FOR ABUTTING ENGAGEMENT WITH THE INTEGRAL PROJECTING ELEMENTS OF SAID BLADES WHEREBY SAID BLADES ARE EACH ADJUSTABLE ROTATIVELY ABOUT A RADIAL AXIS IN RESPONSE TO RECIPROCAL MOVEMENT OF SAID ROD, A FORWARD EXTENSION OF SAID HOUSING HAVING A HYDRAULIC CYLINDER THEREIN ALIGNED WITH SAID PROPELLER SHAFT, A PISTON IN SAID HYDRAULIC CYLINDER HAVING A PISTON ROD IN ABUTTING ENGAGEMENT WITH THE ENLARGED FORWARD END PORTION OF SAID ROD AND ROTATABLE RELATIVE THERETO, A POWER CYLINDER HAVING A SUPPORTING BRACKET AND HAVING FLUID CONDUIT MEANS WHEREBY ONE OF ITS ENDS IS IN FLUID COMMUNICATION WITH THE END OF SAID HYDRAULIC CYLINDER OPPOSITE SAID PROPELLER SHAFT, A PISTON IN SAID POWER CYLINDER HAVING A PISTON ROD EXTENDING OUTWARDLY FROM THE END THEREOF OPPOSITE SAID ONE OF ITS ENDS, A HAND LEVER PIVOTALLY CONNECTED TO SAID BRACKET AND FULCRUMED NEAR ONE OF ITS ENDS AT A POINT WHICH IS ALIGNED AXIALLY WITH SAID LAST MENTIONED PISTON ROD, A CAM SURFACE ON SAID LEVER ADJACENT ITS CONNECTED END, AND A CAM FOLLOWER ON SAID LAST MENTIONED PISTON ROD, THE ARRANGEMENT BEING SUCH THAT SAID BLADES ARE ADJUSTABLE ROTATIVELY ABOUT A RADIAL AXIS, TO THEREBY VARY THEIR PITCH, IN RESPONSE TO PIVOTAL MOVEMENT OF SAID LEVER. 